/*
*    Qizx/open 3.0 beta
*
* This code is the open-source version of Qizx.
* Copyright (C) 2004-2009 Axyana Software -- All rights reserved.
*
* The contents of this file are subject to the Mozilla Public License 
*  Version 1.1 (the "License"); you may not use this file except in 
*  compliance with the License. You may obtain a copy of the License at
*  http://www.mozilla.org/MPL/
*
* Software distributed under the License is distributed on an "AS IS" basis,
*  WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
*  for the specific language governing rights and limitations under the
*  License.
*
* The Initial Developer of the Original Code is Xavier Franc - Axyana Software.
*
*/
using System;
using DataModelException = System.Qizx.Api.DataModelException;
using EvaluationException = System.Qizx.Api.EvaluationException;
using Node = System.Qizx.Api.Node;
using EvalContext = System.Qizx.XQuery.EvalContext;
using Focus = System.Qizx.XQuery.Focus;
using XQType = System.Qizx.XQuery.XQType;
using EmptyException = System.Qizx.XQuery.Impl.EmptyException;
namespace System.Qizx.XQuery.Fn {

    /// <summary>  Implementation of function fn:nilled.   TODO</summary>
    public class Nilled : Function {
        public override Prototype[] Protos {
            get {
                return protos;
            }

        }
        internal static Prototype[] protos;

        public class Exec : Function.BoolCall {
            public override bool evalAsBoolean(Focus focus, EvalContext context) {
                context.at(this);
                Node node = args[0].evalAsOptNode(focus, context);
                try {
                    if (node == null || node.NodeType != System.Qizx.Api.XdmNodeType.Element)
                        throw EmptyException.instance();
                } catch (DataModelException e) {
                    dmError(context, e);
                }

                #region HACK CoShare
                Node nilAttr = node.GetAttributeNode(Function.nil);
                if (nilAttr != null) {
                    string nil = nilAttr.StringValue.Trim();
                    return nil == "true" || nil == "1";
                }
                #endregion
                return false;
            }
        }
        static Nilled() {
            protos = new Prototype[] { Prototype.fn("nilled", XQType.BOOLEAN.opt, typeof(Exec)).arg("node", XQType.NODE.opt) };
        }
    }
}